18 replies to this topic

[Spider]

Sounds like the commutators have been coming to bits. They don't like 'high' RPMs (hence why they are fitted with a bigger pulley than alternators) but even so, with a more or less stock engine, you'd be hard pressed getting enough RPMs from it to do this.

 

Another cause for them coming apart is high current flow through the commutator for a continuous period.

 

I doubt this would be the issue, but just to mention it. The Bearing in the front end is electrically insulated from the frame and this insulation must be maintained. Usually though, if it does short across this, the Bearing fails rather then the issues you are seeing, but, if it doesn't fail, then it will cause the armature to get VERY hot and fail in short time.

[MikeJE]

Sorry for resurrecting this thread, but the alternator that looks like a dynamo (Dynamator? not sure what make) has failed on my 998 mini (it's a '62 traveller but with a replacement 998 engine and negative earth). I took it to a local auto electrician who tested it and confirmed its demise. He said the internal regulators come from China, are poorly made and difficult if not impossible to replace.

 

Has anyone any experience with these and can recommend or suggest something likely to last, please? It's only used for ordinary road travel so no high revving!

 

Many thanks once again.

 

Best wishes

 

Mike

[Spider]

Often a Alternator Regulator from a similar Output and Rotor Resistance can fitted. There are (or were, been a while since I needs to look !) Universal Regulators. Either of these will likely end up being external to the Alternator, but if you look around, you might find one that will fit internally.

 

< Edit: By chance, while looking for something else, I stumbled over a Spare Regulator I used to have in the Rally Car

 

   >

Edited by Moke Spider, 19 October 2019 - 02:04 AM.

[MikeJE]

Thanks Mokespider - My auto electrician has doubts about finding a regulator to fit the expired unit as they come from China, but notice the one in your pic is made by Bosch (or at least is stamped as such!). I may open the unit and see what's inside before I buy a replacement. If it is something I can find a replacement for, I will give it a go as replacements are expensive.

 

If I need to buy a replacement there seems to be three alternatives: Dynamator available from most places at about £150; Minispares and others sell a Dynalite at about £500 (!) and I have seen online a further alternative called a Dynator (see https://www.autoelec...roduct_list/197) for £300 but which seems to have the advantage of a 3 year warranty.

 

Has anyone any experience of using any of these, please?

 

Kind regards

 

Mike